Method and apparatus for making products by sintering and/or melting

Abstract

The invention relates to a method for making metallic and/or non-metallic products 2 , in particular dental products, by freeform sintering and/or melting, in which the products 2 are fabricated layer by layer from a material 5 that is applied layer by layer by means of a computer-controlled high-energy beam 7 , in particular a laser or electron beam. In order to reduce production times, beam 7 irradiates predetermined positions P 1 to P 6 of a layer of a material 5 a plurality of time, namely m times, where m is a whole integer greater than 1. Each of said positions P 1 to P 6 is initially heated during the first irradiation to a temperature below the melting point T melt of the material 5 , and during the mth irradiation to a temperature above said melting point and is completely melted over the entire thickness of the layer in such a way that the material ( 5 ) fuses at said position to the layer thereunder. The invention also relates to an apparatus for performing said method.

The invention claimed is: 
     
       1. An apparatus for making metallic and/or non-metallic products, by freeform melting using a high-energy beam, wherein the apparatus comprises:
 a beam source for generating said beam, 
 a platform for receiving a powder material that can be applied in layers and a controller for controlling the beam, by means of which the beam can be guided by computer control in order to fabricate the products layer by layer from the material, wherein the controller is configured in such a way that, by means of said controller, the beam irradiates predetermined positions of the material a plurality of m times, where m is a whole integer greater than 1, wherein each of said positions is initially heated during the first irradiation to a temperature below the melting point (T melt ) of a single grain of the powder material and during the mth irradiation to a temperature above said melting point (T melt ) and wherein the powder grains are completely melted over the entire thickness of the layer in such a way that the powder grains of the material fuse at said position to the layer thereunder. 
 
     
     
       2. Apparatus according to  claim 1 , wherein m equals 2. 
     
     
       3. Apparatus according to  claim 1 , wherein the controller is adapted to irradiate each of said positions for a first duration (Δt on ), then not irradiate during a second duration (Δt off ), wherein the second duration (Δt off ) is at least exactly as long or twice as long as the first duration (Δt on ). 
     
     
       4. Apparatus according to  claim 1 , wherein m equals 3. 
     
     
       5. Apparatus according to  claim 4 , wherein the controller is adapted to irradiate each of said positions for a first duration (Δt on ), then not irradiate during a second duration (Δt off ), wherein the second duration (Δt off ) is at least exactly as long, twice as long or four times as long as the first duration (Δt on ). 
     
     
       6. Apparatus according to  claim 1 , wherein the controller is configured to guide the beam backward and forward with a first substantially linear movement, the forward movement extending over a longer path than the backward movement. 
     
     
       7. Apparatus according to  claim 6 , wherein the controller is configured to superimpose a second, meandering movement upon said first substantially linear movement. 
     
     
       8. Apparatus according to  claim 1 , wherein the high energy beam is a laser or electron beam. 
     
     
       9. Apparatus according to  claim 1 , further comprising an optical measuring device for measuring the contour of the product, wherein the controller is configured to compare the measured data of said optical measuring device with specified data and to adjust the beam if a deviation is discovered to take account of the deviation thus identified.